Storm Desmond: scientists and media examine role of climate change

AttributionStorm Desmond: scientists and media examine role of climate change

Last weekend, Storm Desmond swept across the UK, bringing very heavy rainfall and gale-force winds to much of northern England, southern Scotland and Ireland. The resulting floods left many homes inundated and at least 60,000 without power.

The past week has seen a national debate in the media about whether climate change contributed to the weekend’s extreme weather. Now a preliminary analysis suggests that the exceptional rainfall totals were 40% more likely because of rising global temperatures.

Carbon Brief takes a closer look at what’s been in the UK’s newspapers this week.

Major incident

In the immediate aftermath of the storm, the media covered the impacts widely. Cumbria was worst-affected by flooding, said the Guardian. The county declared “a major incident” – meaning special arrangements had to be made by the emergency services to cope with the event. The army was drafted in to help rescue stranded locals, noted the Times.

The deluge brought by Storm Desmond set a new UK record for rainfall in a 24-hour period, reported the Telegraph, with 341.4mm falling in Cumbria, topping the previous record of 316.4mm set on 19 November 2009.

Meanwhile, NASA produced a visualisation of the heavy rainfall event hitting the UK.

Visualisation of estimated UK rainfall for the period from 30 November to 7 December 7, 2015, using data from NASA’s Integrated Multi-satellitE Retrievals for GPM (IMERG). Credits: SSAI/NASA/Hal Pierce

Consistent with climate change

With the COP21 climate summit underway just a few hundred miles away in Paris, the debate in the UK soon turned to whether the record-breaking rainfall was fueled by human-caused climate change.

On Sunday, the Guardian quoted Guy Shrubsole from Friends of the Earth:

As climate negotiators fiddle in Paris, Britain floods. Climate change is increasing the frequency of extreme rainfall and floods in the UK and around the world.

Then, on Monday, environment secretary Liz Truss and Labour leader Jeremy Corbyn both linked the extreme weather to climate change, reported Business Green. Truss told MPs in the Commons that extreme weather patterns were “consistent with the trends we’re seeing in terms of climate change”, while Corbyn said they were “in line with scientists’ projections”.

Truss’ comments made the front page of the Times the following morning.

Meanwhile, speaking to Radio 4, Met Office chief scientist Prof Dame Julia Slingo said the evidence pointed towards a link, but it was too early to be sure – as reported by the Metro:

There can’t yet be a definitive answer, but we know that all the evidence from fundamental physics and what we understand about our weather patterns, that there is potentially a role.

And in a speech to the Accounting for Sustainability Summit yesterday, Prince Charles described climate change as a “root cause” of the flooding.

The response in the opinion columns has been swift, with prominent articles from climate sceptics, such as Christopher Booker in the Daily Mail, James Delingpole in the Express, and Andrew Montford in the Spectator.

Booker argues that “legendary downpours of 1897 and 1898” in Cumbria “were comparable to anything experienced in 2015,” while Delingpole says that the claims from Slingo, Truss and Corbyn were “either dishonest, disingenuous or flat-out untrue”.

Yet while it wouldn’t be true to put all the blame of an extreme event at the door of climate change, scientists are able to spot the fingerprints of human activity on our weather. And preliminary results from a rapid, near-time attribution study suggest that climate change increased the chances of the weekend’s exceptional rainfall by 40%.

Using three different methods, scientists identified a “small but robust” increase in the likelihood of the exceptionally heavy rainfall event. The increase is within a range of 5% to 80%, with a central estimate of 40%, notes the story in the Mirror.

The three approaches were the same the researchers used to assess the recent Brazil drought, where they found that climate change had not made the dry spell more likely.

10 years ago we could could never make a link to climate change with a specific weather event. Now we can do it in real time. A positive attribution for an extreme rainfall event like Desmond is still rare.

Storm Desmond is the second extreme weather event the team has analysed in this rapid fashion, reports Financial Times. Earlier this year, the researchers found that the summer’s heatwaves across Europe were as much as four times as frequent because of climate change, the FT adds.

Ten years ago if you asked ‘has climate change increased the risk of this disaster?’, scientists would always say no single event can be attributed to climate change. That has changed.

It’s worth noting that these results are still preliminary, although the researchers have submitted a paper to an academic journal for peer-review.

This isn’t the first time that extreme UK rainfall has been linked to our changing climate. Last year, Otto and her colleagues at Oxford used one of the three methods to show that the probability of an extremely wet winter like the UK’s in 2013-14 was 25% higher than it was before humans started influencing the climate. And a more recent study suggests that the amount of rain the succession of storms dumped on the UK during that winter was seven times more likely because of climate change.